Healthcare Fragmentation and Incident Acute Coronary Heart Disease Events: a Cohort Study

Abstract

Background: Highly fragmented ambulatory care (i.e., care spread across many providers without a dominant provider) has been associated with excess tests, procedures, emergency department visits, and hospitalizations. Whether fragmented care is associated with worse health outcomes, or whether any association varies with health status, is unclear.

Objective: To determine whether fragmented care is associated with the risk of incident coronary heart disease (CHD) events, overall and stratified by self-rated general health.

Design and participants: We conducted a secondary analysis of the nationwide prospective Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort study (2003-2016). We included participants who were ≥ 65 years old, had linked Medicare fee-for-service claims, and had no history of CHD (N = 10,556).

Main measures: We measured fragmentation with the reversed Bice-Boxerman Index. We used Cox proportional hazards models to determine the association between fragmentation as a time-varying exposure and adjudicated incident CHD events in the 3 months following each exposure period.

Key results: The mean age was 70 years; 57% were women, and 34% were African-American. Over 11.8 years of follow-up, 569 participants had CHD events. Overall, the adjusted hazard ratio (HR) for the association between high fragmentation and incident CHD events was 1.14 (95% confidence interval (CI) 0.92, 1.39). Among those with very good or good self-rated health, high fragmentation was associated with an increased hazard of CHD events (adjusted HR 1.35; 95% CI 1.06, 1.73; p = 0.01). Among those with fair or poor self-rated health, high fragmentation was associated with a trend toward a decreased hazard of CHD events (adjusted HR 0.54; 95% CI 0.29, 1.01; p = 0.052). There was no association among those with excellent self-rated health.

Conclusion: High fragmentation was associated with an increased independent risk of incident CHD events among those with very good or good self-rated health.

Figure 1

Absolute adjusted rates of incident coronary heart disease (CHD) events, stratified by healthcare fragmentation status and self-rated general health. Adjusted rates were derived from Poisson models that adjusted for age, gender, race, marital status, educational attainment, income, region, hypertension, hyperlipidemia, diabetes, body mass index, albumin-to-creatinine ratio, C-reactive protein, number of medications, smoking, alcohol use, and lack of social support. Fragmentation status is a time-varying exposure based on the reversed Bice-Boxerman Index (low < 0.85, high ≥ 0.85). See “METHODS” for more details.